I would like to develop a poker odds application that can give the probability of various game situations. Since the application will be mostly statistical analysis, I figured I would see if someone else had already written a library that implements the required mathematics.
I would prefer cross-platform open-source in C++, but that's not a requirement.
This is a subset of Dave's list, but I suggest you look at twodimes.net. It is a web app that uses the pokenum open source library. It is written in C. It does hand enumeration and stats for several poker varieties.